Tool grinder



April 29, 1958 J. R. BELTRAM ETAL. 2,832,179

TOOL GRINDER 2 sheets-sheet i Filed NOV. 17, 1955 mvv WMM* INVENTORS.'

April 29, 1958l J. R. BELTRAM ETAL 2,832,179

TOOL GRINDER 2 Sheets-Sheet 2 Filed Nov. 17, 1955 United States Patent Toor. GRINDER Joachim Richard Beltram, Livingston, and Nicholas Mastro, East Orange, N. J., assignors to International Edge Tool Co., Newark, N. J., a corporation of New Jersey Application November 17, 1955, Serial No. 547,409

2 Claims. (Cl. 51135) This invention relates to tool grinders, and more especially to those of the type which employs an abrasive belt.

Grinders of the mentioned type are well known. They normally employ an electric motor connected by suitable shafting to one of a pair of belt pulleys or wheels, an abrasive belt revolving around the pair. Since such grinders are used to sharpen tools, for example, knives, of various sizes and which are intended for various purposes, much thought has been given to providing the grinders with adjustable tool holders which will enable the user, with safety, to sharpen tools at various angles, as desired.

Another problem incident to the use of grinders of the type mentioned is that of adapting the grinders to irregularities in the size of belt while at the same time furnishing the desired degree of belt tautness during the grinding operation even though the force exerted against the belt during the operation cannot normally be maintained at a constant level. This problem has been met by attempts to provide a so-called free or floating wheel as one of the pair of belt wheels.

As a result of prior efforts grinders of some merit have been developed and marketed successfully. However, it has been found that the known tool holders, and means for cushioning the force on the floating wheel are disadvantageous, for various reasons. For one thing, they involve cumbersome, and consequently expensive, constructions. Also, they are of such nature as to result in grinders of considerable bulk, insofar as area required is concerned. rl`his is a consideration of more importance than may first appear to be the case when it is considered that an important and growing form of grinders of the type mentioned is the portable variety. Aanother disadvantage of known grinders is that the tool holders are above the belt which means that the tool to be sharpened has to be held over the grinder, a situation which results in unnecessary strain on the user, especially when heavy tools, such as butchers cleavers are being sharpened.

it is an object of this invention to provide grinders, including portable cncs, of the type mentioned which are effective and at the same time which avoid the above and other disat' outages of prior grinders.

Fl`his object has been attained in accordance with this invention wherein we provide a tool grinder having a motor, a housi f. a pair of upper and lower belt wheels within sai housing and around which the abrasive belt rotates, said lou/er wheel being coupled to the motor, the upper wheel being the driven wheel. The latter is vvertically mo dole, whether at rest or in operation. An opening across the front of the housing between the belt wheels is provided and a guide plate integral with the housing is located in the opening so that the belt passes over it, i. e., iu front of it, during operation of the grinder.

Our novel tool holder is located in front of the guide plate and comprises a tool guide member against which are xedly secured to each other the tool is placed in known manner for sharpening. The tool guide member extends across the opening in the housing. On both of its sides the tool guide member has pivoted thereto connecting arms which are secured to the housing, yor to means associated therewith. One of the connecting arms is tixedly secured to one side of the housing. The other connecting arm is detachably secured to the other side of the housing.

ln addition to the foregoing or first pivoted means, the tool guide member has additional pivoted means comprising (a) a generally-downwardly extending arm pivoted to the tool guide member at a point further removed from the guide plate than the point of first pivot, or in other words, in front of the rst pivot point; and (b) a generally-forwardly extending arm adjustably pivoted to the housing at a lower point than that to which the first pivoted means are secured. Arms (a) and (b) substantially at right angles to each other.

While we presently prefer the just-described construction for the above additional pivoted means we do not wish to be restricted thereto. Other means pivoted to one side of the tool guide member can be used so long as the point of pivot is farther from the guide plate than the first pivot point and the means are secured to the housing at a lower point than that to which the first pivoted means are secured.

With the foregoing in mind, our invention consists of certain novel features of construction and combinations and arrangements of parts, which will be more fully hereinafter described, and which will become apparent from the following description taken. in connection with the accompanying drawings in which like characters represent like parts throughout and which form a part hereof.

in the drawings:

Fig. l is a front elevation of a preferred embodiment of our novel portable tool grinder showing the tool holder in a normal grinding position with an abrasive belt in place around the pair of belt wheels;

Fig. 2 is a side elevation similar to Fig. l, the grinder being viewed from the side opposite to that near the motor, a representation of a tool to be sharpened being also shown in sharpening position, part of the housing being removed to expose the belt wheels;

Fig. 3 is a fragmentary side elevation similar to Fig. 2

except that (a) the View is taken from the motor side and (b) the housing is not broken away;

Fig. 4 is a fragmentary partial sectional view taken along the line d-d of Fig. 3; and

Fig. 5 is a sectional view of the housing and interior, taken along the line S-5 of Fig. 4.

Referring to the drawings, our grinder is secured to a suitable base l0 which is supported by legs 12, preferably of rubber or other suitable resilient material. An electric motor ld having electrical cord lo is connected to a source of electricity (not shown). A switch 18 is used to turn the motor ld on and off.

The motor 1d is connected by suitable coupling means (not shown) to driving shaft 20 which passes through the housing 22. Driving belt wheel 24 is secured to the shaft Ztl by means of set screw 26 so that the wheel 24 rotates with shaft Ell.

Located above the wheel Z4 is another belt wheel 28 having flanged circumferential edges 30. Wheel 28 is free to rotate around fixed shaft 32 being held in place thereon by cotter pin 3d and washer 36 which abuts against the interior of the housing 22. The shaft 32 passes through it These are secured to the housing 22 by means of bolts 44 and form a key-way into which the keyed member 46 of generally cruciform horizontal cross-section is slidable, since the shaft 32 is integral with keyed member 46. For ease in moving member 46 a knurled handle 48 is secured to it.

Tension spring 59 is located under the keyed member 46 engaging a lug 52 thereunder and a lug 54 upwardly disposed from the bracket 56 secured to the exterior of the housing 22. The size and strength of the spring t) is such that when the grinder is in operating position the spring 5i) exerts an upward force on the key member 46 which force in turn is transmitted through the shaft 32 to the upper wheel 28. When the grinder is not in operation there is little or no tension on the key member 46, and hence on wheel 28. In the latter case upward movement of the wheel 28 is restricted normally by the 'termination of the slot 32, although, if desired, other suitable stop means (not shown) may be provided.

A conventional abrasive belt 58 of the endless type is placed around wheels 24 and 2S in the usual manner. The belt 58 is of such size that it does not iit in place until the upper wheel 28 is lowered by pushing key member 46 down.

The front 60 of housing 22 has an opening 62. In this opening is a guide plate 64 so spaced that the belt 58 passes in front of the guide plate 64 as shown in Figs. 2 and 3.

Located in front of the opening 62 is a tool guide member 66 extending across the opening. As shown, the member has a pivotally movable plane surface 63 terminating on each side with substantially parallel portions 70, 72 which give the member 66 the appearance of an inverted U.

The lower part of portion 70 is pivoted at 106 to the arm 74 integrally secured to the housing 22. At a corresponding point 108 on portion 72 one end of arm 76 is pivoted. The arm 76 has a cutsout 7S near its o-ther end 80. This cut-out 78 engages with rod 82 and the arm 76 is held in place thereon by means of the large knurled screw 84.

Located in front of the point of pivot of arm 70 and arm 74 is a second pivot point 86. At this point is pivotally engaged the generally-downwardly extending connecting member 88. This member 88 is rigidly attached to generally-forwardly extending connecting member 90, substantially at right angles, as shown at 92. The rear end of member 90 is pivotally secured to rod 94 secured to the housing 22. Member 90 is secured in any desired position on rod 94 by means of the handle 96 on cap nut 98 notched at one end 100 to aid in obtaining a secure engagement of the member 90 to the rod 94.

The operation of our novel grinder is simple. To place it in condition for sharpening tools the face 192 of the housing 22 shown broken away in Fig. 2 is removed by means not shown. The belt 58 is placed into position around belt Wheels 24 and 28, a downward force being applied to key member 46 and/or handle 45% in order to force wheel 28 down sufliciently to permit the belt S8 to pass around it. The belt 5S and the wheels 24 and 28 are of such size that when downward pressure on key member 46 and/ or handle 48 is released the wheel 28 is forced upward by tension spring 50. As a result the belt 58 is maintained in taut condition around the wheels 24 and 28. The tanges 30 on wheel 28 help to contain the i belt 58 and keep `it in alignment. The face 162 of the housing 22 is then secured to the latter.

The tool guide member 66 is then adjusted so that when the tool 194 to be sharpened is placed on the surface 6 with the edge to be sharpened against the belt 58 the proper sharpening angle is obtained. To adjust this tool guide member 66, all that is necessary to be done is to loosen cap nut 98 by turning handle 96 and then either raising or lowering the arm 96, which causes the guide member 66 to pivot around points 106, 1G55, thereby causing the plane surface to make a small or large angle with the belt SS. The angle shown in Figs. 2 and 3 indicates a position found to be satisfactory for many purposes.

When the desired tangle is obtained the guide member 66 is secured in position by tightening cap nut 9S by means of handle 96.

The tool 164 is then placed on the surface 68 as shown in Figs. 2 and 3 and the switch 18 is turned on. The tool 104 may be moved transversely across the belt 58 if desired to aid in the sharpening process. After one edge of the tool 104 is sharpened it is reversed, i. e., the other edge to be sharpened is placed against the belt 5S. The actual sharpening step is conventional and for this reason no further details thereon are given.

departing from the spirit or scope thereof. We aim in the appended claims to cover all such modifications and changes.

We claim:

l. A tool grinder ofthe type which employs an abrasive belt, comprising a motor, a housing, a pair of upper and lower belt wheels within said housing and around which the abrasive belt rotates, said lower wheel being a driving wheel :associated with said motor, said upper wheel being the driven wheel and vertically movable at rest and in opertaion, an opening across the iront of said housing intermediate said belt wheels, a platen in said opening secured to said housing and located so that the belt passes in front of said platen and is supported thereby and a tool holder in front of said platen and which comprises a U tool guide member extending across said opening, said member having legs pivotally mounted to said housing on both sides thereof and having an actuating arm pivotally supported on the housing and pivotally connected to one leg of said tool guide member at a point farther removed from said platen than the iirst pivoted means, whereby the angle of the tool holder may be adjusted with respect to the belt.

2. A tool grinder in accordance with claim 1 having a locking member for said actuating arm.

References Cited in the le of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain Dec. 20, 1950 

